The present invention relates to incendiary devices which are designed to ignite combustible material and are dispersed by means of an explosive charge. Such devices have both military use in the destruction of property and war materiel and civilian application, for example, in starting backfires for forest fire control.
Several types of incendiary devices of the general type contemplated by the present invention have been used in the past. One common type has used a pelleted flowing, powdery mixture of metal and oxidizer which is dispersed upon explosion of an explosive charge. Such devices, of course, inherently have an obvious hazard insofar as handling is concerned because the materials are spontaneously reactable. Further, they are not totally satisfactory because the pellets tend to disintegrate and burn too rapidly or to detonate themselves. The explosive charge tends to disperse the powders in an erratic manner. Thus, neither uniformity nor extent of distribution is often optimum.
Another type of known device makes use of fragments of solid compositions such as zirconium-misch metal, or Thermits. These materials can be cast into a proper form such as the lining of a shell casing which is then filled with the explosive charge. They tend to suffer, however, from handling difficulties due to vacuums and pressures needed for fabrication and to early burn-out and failure to ignite ambient combustible material. Further these materials are brittle and tend to disintegrate into extremely fine particles upon exposure to the pressures of detonation resulting in a quick burning powder. Misch metal and zirconium require outside oxygen for burning and thus are ineffective under water or other liquids or at high altitudes where oxygen is scarce.